The present invention relates to the allocation of fractions or components obtained from herbs in microarrays on a plastic substrate. The plastic substrate containing allocated fractions or components of herbs is useful as a platform for screening for active ingredients contained in the herbs that have specific pharmacological or therapeutical functions.
The use of herbs or an extract or fraction thereof as a medicine has been well known for so many years. For example, the bark of willow tree has been used as an antipyretic and analgesic agent for more than 2000 years, and an extract from the bark of Peruvian Cinchona has been used for the treatment of malaria since the 17th century.
Up to date, however, only a few active ingredients contained in herbs that have specific pharmacological or therapeutical functions were discovered. For example, salicin, a salicyl alcohol glucoside, was recognized as an active ingredient in the bark of willow tree that exhibited antipyretic and analgesic properties in the middle of 20th century, and quinine was recognized as an active ingredient in the bark of Peruvian Cinchona that exhibited an effect on the treatment of malaria in 1820.
The discovery of an active ingredient from a herb was laborious and time-consuming. For example, taxol, an anti-tumor drug, was isolated from the bark of North American yew tree Taxus brevifolia, after the work of screening of more than 110,000 samples derived from more than 35,000 plant genera collected worldwide. In general, he common strategy in the discovery of an active ingredient from a herb was to identify the function(s) of the herb in human body and to apply various physical and chemical procedures for isolating active fraction(s) of the herb and then for separating and purifying the active ingredient. There was no general guideline for the discovery of an active ingredient from a herb. Though the understanding of pathogeny in the molecular or gene level based on the development of pharmacology, cell biology and molecular biology was significantly increasing, and the shotgun screening of an extract of a herb for hitting desired active ingredient(s) contained in the herb was developed, however the discovery of an active ingredient from a herb was still a laborious, trial-and-error work and progressed in a slow pace.
There has been a demand in the art to develop a new tool to conduct a rapid screening for active ingredients from herbs or an extract or fraction thereof that have specific pharmacological or therapeutical functions.
The technique of immobilization of large biological molecules on a solid substrate (e.g. nylon membrane), such as Western blot for immobilizing peptides or proteins, Southern blot for immobilizing DNA fragments and Northern blot for immobilizing RNA fragments, was used in the art, and the immobilized molecules interacted with a labeled probe and then the resultant probe-labeled molecules were imaged. For example, enzyme-linked immunosorbent assay (ELISA) involved immobilizing large biological molecules on a substrate, interacting the immobilized molecules with a labeled substance, and then coloring and imaging the resultant labeled molecule(s). The ELISA could be performed on a conventional 96-well microplate.
Recently, the high-density gridding technology was used in the art for detecting the presence of a target material in biological samples (e.g. DNA or proteins), wherein the samples were immobilized in a predetermined array on a solid substrate (e.g. glass slide) and then were hybridized with a labeled probe, followed by washing and imaging. In applying the high-density gridding technology, the biological samples were known DNA or protein pools that were homogeneous, and the labeled probe was an unknown or unidentified substance that was heterogeneous. The advantage of the high-density gridding technology resided in that a tiny volume of a sample could be immobilized in a small gridded area on the surface of the substrate and thousands of samples could be manipulated simultaneously. Further, a computer-controlled three-axis robot and a unique pen tip assembly (i.e. microarrayer) could be used to generate the high-density, gridded arrays of biological samples on the surface of a substrate.
So far, however, the high-density gridding technology was used for analyzing just macromolecules, such as proteins and nucleic acids, where the immobilize samples on the surface of a solid substrate (e.g. glass slide) were homogeneous. There was no teaching or suggestion in the art that heterogeneous samples containing large, biologically active molecules (such as proteins or nucleic acids) or small, biologically active molecules (such as secondary metabolites) could be immobilized on the surface of a solid substrate (e.g. plastic slide). There was also no teaching or suggestion in the art that homogeneous or heterogeneous samples obtained from herbs or extracts or fractions thereof could be immobilized on the surface of a solid substrate (e.g. plastic slide), especially in a microarray format. Furthermore, there was no teaching or suggestion in the art that by applying the high-density gridding technology, a high throughput screening for biologically active molecules from herbs could be conducted with the homogeneous or heterogeneous, unknown samples allocated on the surface of a solid substrate (e.g. plastic slide) that interacted with homogeneous or heterogeneous, known labeled probe(s).
Therefore, the present invention discloses a new platform for screening for active ingredients from herbs with homogeneous or heterogeneous, known labeled probe(s), which comprises homogeneous or heterogeneous ingredients from herbs that are immobilized on a solid substrate (e.g. plastic slide).
The present invention discloses a new platform, named herbal chip, comprising a plastic slide, a coating as a spacer on the plastic slide, and fractions or components obtained from herbs that are independently allocated in microarrays on the coating. The herbal chip of the present invention is useful for screening for active ingredients contained in the herbs that have specific pharmacological or therapeutical functions.
The present invention also discloses a method for producing the herbal chip.
Further, the present invention discloses a method of using the herbal chip for screening for active ingredients contained in herbs.